Device employing fluid electrodes



Dec. 22, 1936. l. BALINKIN ET AL DEVICE EMPLOYING FLUID ELECTRODES Filed April 7, 1932 Flq. 2

. INVENToR.

By MEM (ZZ/zw a MLU ATTORNEYS Patented Dec. 22, 1936 uNiTED STATES PATENT OFFICE lClaim.

Our invention applies in one of its aspects to the general class of electrical devices employing electrodes or contact members of uid material,

usefulness in the electrical art. Other phases of 1 our invention relate to particular classes of such devices, and the specic embodiment employed D herein for purposes of illustration is a mercury vapor arc device.

It is an object of our invention to .provide means in' devices of the class referred to for maintaining a body of liquid conductive substance in contact with a suitable terminal so that said body of liquid may serve as a contact member, electrode terminal, or the like, under substantially all conditions of use of the device. Consequently, it is an object of our invention to provide means in an electrical device of the character described for vmaintaining a portion of mercury, or the like, in position in association with a conductor, irrespective of the position, location, or condition of the remainder of a body of liquid conductive substance in the device.

It is also an object of our invention to provide means whereby terminal members may be less subject to deleterious conditions in the use of the device.

0 Yet another object of our invention is the provision of improvementsV in mercury vapor arcs, as will hereinafter be more fully described.

These and other objects of our invention which will be set forth hereinafter or will be apparent 5 to one skilled in the art upon reading these specications, we accomplish by that certain construction and arrangement of parts of which we shall now describe the aforesaid exemplary embodiment.

0 'Ihe drawing shows:

In Fig. 1' a side elevation of a mercury vapor lamp embodying our invention.

Fig. 2 is a front elevation thereof.

Hitherto in mercury vapor arc lamps, and in 5 other types of electrical devices employing liquid electrodes or terminal agents, diiculty has been experienced in maintaining a body. of the liquid continuously in contact with the necessary terminal elements of the device. Thus it has 0 been the practice in lamps to seal into an envelope of pyrex, glass, quartz, or the like, ter- -minal wires or elements of tungsten, or other refractory metal, with or without an intermediate sealing substance. In the operation of the 5 device, it is desired to keep a pool of mercury in constant contact with the terminal element, so

that the mercury itself and not the terminal element will serve as the actual electrode. In arc lamps of the kind which are started by tilting, the tilting operation very frequently removes 5 the mercury from one of the terminal elements, which upon the initial striking of the arc becomes the actual electrode, and is subjected for a short period to exceedingly high temperatures. This is disadvantageous in two respects: First, that some of the metal of the terminal is volatilized and mirrors out upon the walls of the vessel, thereby cutting down the light transmitted therethrough, and secondly, because the heat developed in the terminal itself is likely to disrupt the seal and cause the vessel to fail. Somewhat the same problem, encountered in devices of the mercury switch class, has been solved by locating the terminals in wells which are always kept full of mercury, but this in turn limits the angle through which the switch element may be tilted during the operation thereof, and consequently limits the use of the switch.

A salient object of our invention comprises means for maintaining a body of mercury, or the like, in contact at all times with the terminal elements, quite irrespective of the disposition of the remainder of the liquid substance. To this end we 'locate our terminal elements in portions of the vessel which are larger than said elements so that the liquid may lie thereabout, but we provide between such portions and other or working portions of the device, a constriction of such character as will maintain the mercury in the space aforesaid, while permitting suicient volume of mercury to exist in the constriction to provide a device of low electrical resistance.

In Figs. 1 and'2, we have shown the mercury vapor lamp consisting of a straight tube l and a branch tube 2. The upper portion of the straight tube indicated at 3 is adapted to serve as a condenser, while the lower portion 4 serves as one of the terminals of the device and may be of shorter effective length than the branch tube 2. The terminals in this device are sealed into the ends of the portionsd and 5, and are indicated at 6 and l, which may be thought of as wires of tungsten, or the like, sealed into the envelope, with or`without intermediate sleeves. The envelope may, of course, be of pyrex, quartz, or any other suitable material for the purpose desired, and the sealing in of the terminals may be done by any of the known suitable methods. The inner ends of the terminals 6 and 1 lie within spaces indicated at 8 and 9, which are adapted to be 55 ways may vary over considerable limits.

filled with mercury, or other liquid conductive agent as shown. Ahead of these spaces we have formed in the envelope, constrictions comprising thickened portions I0 and II in the envelope, and having a constricted passageway I2 and I3. The exact dimensions of these constrlcted passage- The factors which bear thereon primarily are: that the passageways shall be small enough so that the surface tension of the mercury or other liquid conductive agent employed will be suillcient to hold in place the body thereof within the spaces v 8 and 9 when the tube is tilted so as to send the remainder of the liquid therein into some other portion; but they should not be so small in crosssectional area as to create an unduly high resistance for the passage of current through the conductive liquid in the said constricted openings. In an ordinary small mercury vapor lamp these constricted passageways may be of the order of 5; of an inch in diameter, and will give excellent results, but thesedimensions are not limiting.

When the tube or lamp is tilted, tlle mercury or other conductive liquid breaks at the said constricted passageways so that under all ordinary conditions of use the liquid in the spaces 8 and 9 remains in position, and at all times completely covers the terminals 6 and l.

In the device of Fig. 1 a tilting in any direction, followed by a return of the device so that the tube I is substantially vertical, will result in a starting of the arc. For example, the device may be tilted first in a counter-clockwise direction so that the body of mercury I4, lying above the constricted passageway I3, will spill over into the condenser tube 3 through the rounded neck I5. Then if the tube is tilted in a clockwise direction the excess mercury will spill back through the neck I5, forming instantaneously a continuous stream between a body of mercury I6 in the portion 4 and the body of mercury I4. Equilibrium is attained when the bodies I6 and I4 are in the position shown, the depth of the body I6 being maintained by gravity at the lower inside surface of the neck I5. The arc, cf course, is maintained between the body I6 and the body I4, through the neck I5, and when the lamp is used for technical purposes, light is ordinarily taken from that portion of the column of the arc which exists in the straight tube portion 2. When, due to the heat of the arc, the mercury is evaporated either from the body I4 or from the body I6, the vapor passes up into the portion 3, where it condenses into liquid mercury again, dropping down to join the body I6. As this body increases in bulk, any excess of the mercury will spill over through the neck I5 to maintain the level of the body I4.

The type of arc lamp which we have illustrated in our drawing is a type suitable for direct current operation, and as such it makes; no difference which terminal of the arc is positive. The shape which we have given our device gives new and remarkable results, and it is possible to start Another advantage of our electrode construction as shown is that whereas in lamps in the past there has been a disadvantageous transmission of heat from the mercury at the arcing surface tothe terminal device, both by conduction and by convection, in our device conduction is greatly minimized by the relatively small cross section of the mercuric body in the constricted passageways I2 and I3, and convection currents can be effective only above and below these passageways. In operation, the terminal portions of our lamp stay relatively quite cool, usually not uncomfortably warm to the fingers, whereas great heat is developed at the surface of the bodies I4 and I6, and therebetween. In our construction the chief way in which heat is transmitted to terminal ,5 is by direct radiation, since conduction and convection through the mercury .trode construction, since it will be obvious that it is applicable to other devices than the exemplary embodiment herein disclosed. It will be applicable, for example, to mercury switches and the like, and will have the advantage of maintaining a body of mercury at all times in contact with the terminals. In this way not only may the permissible angle'of tilting of the switch be increased if desired to 360 degrees, but also the construction of mercury switches may be greatly simplied. A straight tubing with one of our terminal constructions at either end and a sumcient body of mercury therebetween to bridge the gap between the terminal constrictions when the tube is substantially in horizontal position, may be tilted through any angle desired, or may be mounted directly upon a rotating shaft to serve as a current interruptor, and will be as accurate as and more positive in its action than mercury switches heretofore constructed.

Our arc lamp has specic advantages in that the arc is not struck through or around complicated glass constructions which are likely to fuse or change their shape during the operation of the device, and in that the lamp lasts longer, and the arc stays litthroughout the entire period of the action of the electric current without interruption.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:

In a mercury vapor arc lamp, an envelope comprising a longer and a shorter leg, each having a terminal connection at one end, the other end of the longer leg joining the other end of the shorter leg by a portion regularly curved onthat said condensing portion at its free end is 75 enlarged, said shorter leg comprising, for a distance substantially half of its length between its terminal connection and the junction o! the longer leg, a chamber in which mercury is to be trapped adjacent to the terminal connection, and said longer leg having a chamber of length substantially equal to the chamber in the shorter leg to trap mercury around the terminal connection of said longer leg, said envelope containing a quantity of mercury suillclent to fill said chambers, to fill the remainder of the shorter leg from its chamber to the Junction of the longer leg with the shorter leg, and to i111 the chamber of the longer leg and to occupy said longer leg exteriorly of the chamber thereof to a length substantially equal to that of extent from the chamber of the shorter leg to said junction, and the two legs and said condensing portion of said envelope having their axes in substantially a single plane, said chambers for trapping the mercury around the terminal each being dened by modication oi' the walls of the respective leg of the envelope which forms a passage betweenthe chamber and the remainder o! the leg which is so constricted that when the lamp is inverted or tilted to any degree, a substantial proportion or the mercury is trapped during the inversion or tilting within the chamber around the respective terminal.

ISAY BAHNKIN. DARE A. WELLS. 

